In the U.S., on the house side of the service entrance current carry components (wiring, outlets, switches) must be sized to carry 100% of rated load while the over current devices (circuit breakers) are designed to carry 80% on a continuous basis with trip at 100%. The size of the main breaker (service disconnect) must meet a minimum that is calculated based on known loads like ovens, dryers, etc. plus a "general lighting load" of 3 watts/per square foot. These days most homes ending up with a 200 amp service based on the typical size and appliance complement.
The utilities on the other hand are free to size their distribution system based on average demand and load thing as their engineers deem fit. It is not uncommon to see a house with a 4/0 gauge service entrance connection yet the utility will supply this with a cable 2 sizes smaller. the same thing hold true for the distribution transformer. A typical 25 KVA transformer will supply a connected average load of 25-30KVA with an allowable overload of 200%.
Then there is the transmission side of things. As electricity demand has increased over time the utilities have responded by increasing the distribution voltage (for the same size wire the capacity goes up in proportion the square of the voltage). Pre-WWII a 9600/4800 volt system was state of the art. Nowadays, 12.47/13.8KV and 21KV systems are the norm. Upping the distribution voltage much beyond these voltages will be very difficult because the insulation requirements become daunting (some cities still have 9600 volt systems in areas for these reasons).
Ironically, generation is less of a concern because charging will typically take place at night when heavy industrial loads are off-line. To a point this will tend to help the utilities by acting as a type of load leveling.
The current system (no pun intended) works because on the average the total utility system load is very predictable and has grown at a predictable rate. A well used commuter electric car's charging needs are probably equal to the average use of a typical home. Electric car charging will cause a step function change in average demand thus throwing off the engineering model used by the utility for sizing of the distribution system. It will indeed be a problem for utilities.
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In the U.S., on the house side of the service entrance current carry components (wiring, outlets, switches) must be sized to carry 100% of rated load while the over current devices (circuit breakers) are designed to carry 80% on a continuous basis with trip at 100%. The size of the main breaker (service disconnect) must meet a minimum that is calculated based on known loads like ovens, dryers, etc. plus a "general lighting load" of 3 watts/per square foot. These days most homes ending up with a 200 amp service based on the typical size and appliance complement.
The utilities on the other hand are free to size their distribution system based on average demand and load thing as their engineers deem fit. It is not uncommon to see a house with a 4/0 gauge service entrance connection yet the utility will supply this with a cable 2 sizes smaller. the same thing hold true for the distribution transformer. A typical 25 KVA transformer will supply a connected average load of 25-30KVA with an allowable overload of 200%.
Then there is the transmission side of things. As electricity demand has increased over time the utilities have responded by increasing the distribution voltage (for the same size wire the capacity goes up in proportion the square of the voltage). Pre-WWII a 9600/4800 volt system was state of the art. Nowadays, 12.47/13.8KV and 21KV systems are the norm. Upping the distribution voltage much beyond these voltages will be very difficult because the insulation requirements become daunting (some cities still have 9600 volt systems in areas for these reasons).
Ironically, generation is less of a concern because charging will typically take place at night when heavy industrial loads are off-line. To a point this will tend to help the utilities by acting as a type of load leveling.
The current system (no pun intended) works because on the average the total utility system load is very predictable and has grown at a predictable rate. A well used commuter electric car's charging needs are probably equal to the average use of a typical home. Electric car charging will cause a step function change in average demand thus throwing off the engineering model used by the utility for sizing of the distribution system. It will indeed be a problem for utilities.
The plant family that produces the "apple" Malus domestica . So I guess this would this be, "Malus of afterthought"?